Reclosing method and device of active power distribution network

Abstract

The invention discloses a reclosing method and device for an active power distribution network. The method comprises the steps that when it is determined that the active power distribution network starts reclosing, a reclosing mode is determined; if the mode is the non-voltage detection mode, detecting whether the active power distribution network has a non-voltage detection condition or not through a reclosing controller, and obtaining a first detection result; if the mode is the communication type reclosing mode, detecting whether the active power distribution network has a communication condition or not through a reclosing controller, and obtaining a second detection result; when the first detection result shows that the voltage of the line side before protection tripping is not zero, executing non-voltage detection reclosing operation; and when the second detection result shows that the active power distribution network has the communication condition and the reclosing controller receives an off-network message that all the inversion type distributed power supplies in the active power distribution network are off-network, communication type reclosing operation is executed. According to the invention, the technical problem of low power supply reliability caused by many limitations during reclosing of the active power distribution network in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the field of electrical engineering relay protection, and in particular to a reclosing method and device for an active power distribution network. Background Art

[0002] In the process of active distribution network fault handling, it is necessary to comprehensively consider the coordination relationship between line outlet protection, distributed energy resource (DER) off-grid time and reclosing. The access of DER changes the distribution network from a traditional single-power radial network to a distribution network with a multi-terminal power structure. When a fault occurs on the line where the DER is located and the protection is activated, if the DER is not off-grid and continues to supply power to the fault point, the arc at the fault point may not be extinguished, and problems such as asynchronous reclosing or unsuccessful reclosing may occur when the reclosing is activated, reducing the operational reliability of the distribution system. Therefore, the reclosing action time of the active distribution network should be coordinated with the off-grid time of the DER.

[0003] When reclosing the active distribution network, the inverter interfaced distributed energy resource (IIDER) is cut off by anti-islanding protection. The traditional reclosing method is to wait for about 2 seconds after the protection trips, and then reclose the distributed energy resource after it is disconnected from the grid. However, the reclosing waiting time of this scheme is long, which affects the reliability of power supply.

[0004] In order to ensure that DER is off-grid when reclosing, many scholars have proposed strategies for checking no-voltage reclosing. For example, the prior art proposes that DER has different effects on the reclosing impact current according to its different access points, and proposes that it is necessary to ensure that DER is off-grid before reclosing. For the power supply side, a voltage-checking reclosing is used, and the DER side needs to adopt a synchronous reclosing solution. However, the no-voltage check cannot be distinguished from the zero-voltage condition of a three-phase metallic fault, and when the voltage transformer on the line side is disconnected, the no-voltage check method fails, and the impact problem of reclosing on the fault cannot be solved.

[0005] Distributed current protection, longitudinal protection and reclosing technology based on optical fiber and 5G communication technology are increasingly used in distribution networks. For example, in the prior art, a distribution line adaptive reclosing method based on topology identification is proposed to solve the problem that the topology structure of the distribution line changes due to operations such as load switching and section isolation. However, the reclosing scheme based on communication has high requirements on the reliability of communication. Once the communication fails or the information is wrong, the reclosing may fail.

[0006] Therefore, the current active distribution network reclosing strategies can be divided into three categories: local delay coordination, communication and voltage detection. Among them, the local delay coordination method needs to consider the fault ride-through of distributed power sources, and is usually coordinated with the longest anti-islanding protection action time to achieve reclosing, which leads to a longer waiting time for reclosing and affects the reliability of power supply.

[0007] If a voltage transformer is installed on the distribution line side, the no-voltage detection method can be used to identify the DER disconnection status based on the detected line-side voltage. However, when the line-side voltage transformer is disconnected, the no-voltage detection method fails and still cannot solve the impact problem of reclosing on the fault, resulting in power supply restoration failure. In practice, many substations are not equipped with line-side voltage transformers due to space constraints, resulting in the inability to implement the no-voltage detection reclosing method in many scenarios.

[0008] In scenarios with peer-to-peer communication conditions, DER can be removed by remote tripping, thereby coordinating with the reclosing switch. The communication-based reclosing solution can achieve rapid reclosing and quickly restore power supply, but this solution has high requirements on the reliability of the communication channel. Once the communication fails or the information is wrong, it may cause the reclosing to fail.

[0009] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0010] The embodiments of the present invention provide a reclosing method and device for an active distribution network, so as to at least solve the technical problem in the related art that the active distribution network has many limitations when performing reclosing, resulting in low power supply reliability.

[0011] According to one aspect of an embodiment of the present invention, a reclosing method for an active distribution network is provided, comprising: when it is determined that the active distribution network starts reclosing, determining the reclosing mode of the active distribution network; when it is determined that the reclosing mode is a no-voltage detection mode, detecting whether the active distribution network has a no-voltage detection condition by means of a reclosing controller of the active distribution network, and obtaining a first detection result; when it is determined that the reclosing mode is a communication reclosing mode, detecting whether the active distribution network has a communication condition by means of the reclosing controller, and obtaining a second detection result; when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping, controlling the active distribution network to perform a no-voltage detection reclosing operation; when the second detection result indicates that the active distribution network has a communication condition, when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid, controlling the active distribution network to perform a communication reclosing operation by means of the reclosing controller.

[0012] Optionally, the reclosing method for the active distribution network also includes: when the first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping, determining that the active distribution network does not meet the no-voltage detection condition, and locking the no-voltage detection reclosing operation of the active distribution network; obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all the inverter-type distributed power sources have been disconnected from the grid, performing a reclosing operation on the active distribution network.

[0013] Optionally, the reclosing method for the active distribution network also includes: when the second detection result indicates that the active distribution network does not have communication conditions, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all the inverter-type distributed power sources have been disconnected from the grid, performing a reclosing operation on the active distribution network.

[0014] Optionally, controlling the active distribution network to perform a no-voltage reclosing operation includes: when it is detected that the line side voltage of the active distribution network is 0, after waiting for a first predetermined period of time, controlling the outlet circuit breaker of the active distribution network to reclose through the reclosing controller; after determining that the outlet circuit breaker is reclosed, ending the no-voltage reclosing operation.

[0015] Optionally, when the second detection result indicates that the active distribution network has communication conditions, when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid, the reclosing controller controls the active distribution network to perform a reclosing operation, including: sending control information for disconnecting the grid-connected switches of the inverter-type distributed power sources to the grid-connected switch controllers of the grid-connected switches of all the inverter-type distributed power sources according to pre-configured topology information, so that the grid-connected switch controller controls the grid-connected switches to trip based on the control information after receiving the control information, and sends the off-grid message to the reclosing controller; after the reclosing controller receives the off-grid message, after waiting for a second predetermined time, the reclosing controller controls the outlet circuit breaker of the active distribution network to reclose; after determining that the outlet circuit breaker is reclosed, the reclosing operation is ended.

[0016] Optionally, the reclosing method for the active distribution network also includes: after the reclosing controller does not receive the off-grid message, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all the inverter-type distributed power sources have been off-grid, performing a reclosing operation on the active distribution network.

[0017] Optionally, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network includes: obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network through a first formula, wherein the first formula is: t a Indicates the duration of the anti-islanding protection, U p.u. It represents the measured per unit value of the bus side voltage of the active power distribution network.

[0018] Optionally, determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action includes:

[0019] The reclosing action duration required for the active distribution network to perform reclosing is determined by a second formula according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action, wherein the second formula is: t r Indicates the duration of the reclosing action, t a represents the duration of the anti-islanding protection, Δt represents the fault arc extinction time of the active distribution network, t Ⅱ Indicates the action time of current II in stage protection, t Ⅲ It indicates the action time of current stage III in the stage protection. Stages I, II and III refer to the stage current protection configured for the distribution line outlet protection.

[0020] According to another aspect of an embodiment of the present invention, a reclosing device for an active distribution network is further provided, comprising: a first determination module, for determining the reclosing mode of the active distribution network when it is determined that the active distribution network starts the reclosing; a first detection module, for detecting whether the active distribution network has a no-voltage detection condition through a reclosing controller of the active distribution network when it is determined that the reclosing mode is a no-voltage detection mode, and obtaining a first detection result; a second detection module, for detecting whether the active distribution network has a no-voltage detection condition through a reclosing controller of the active distribution network when it is determined that the reclosing mode is a communication reclosing mode, and obtaining a first detection result. The first operating module is used to control the active distribution network to perform a no-voltage reclosing operation when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping; the second operating module is used to control the active distribution network to perform a communication reclosing operation through the reclosing controller when the second detection result indicates that the active distribution network has the communication conditions and when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid.

[0021] Optionally, the reclosing device of the active distribution network also includes: a first processing module, which is used to determine that the active distribution network does not meet the no-voltage detection condition and lock the no-voltage detection reclosing operation of the active distribution network when the first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping; a first acquisition module, which is used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; a second determination module, which is used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; a third operation module, which is used to perform a reclosing operation on the active distribution network when the reclosing action duration arrives and it is detected that all the inverter-type distributed power sources have been disconnected from the grid.

[0022] Optionally, the reclosing device of the active distribution network also includes: a second acquisition module, used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network when the second detection result indicates that the active distribution network does not have communication conditions; a third determination module, used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; a fourth operation module, used to perform a reclosing operation on the active distribution network when the reclosing action duration arrives and it is detected that all the inverter-type distributed power sources have been disconnected from the grid.

[0023] Optionally, the first operating module includes: a first control unit, used to control the outlet circuit breaker of the active distribution network to reclose through the reclosing controller after waiting for a first predetermined period of time when it is detected that the line side voltage of the active distribution network is 0; a first ending unit, used to end the no-voltage reclosing operation after determining that the outlet circuit breaker is reclosed.

[0024] Optionally, the second operation module includes: a sending unit, used to send control information for disconnecting the grid-connected switches of the inverter-type distributed power sources to the grid-connected switch controllers of the grid-connected switches of all the inverter-type distributed power sources according to pre-configured topology information through the reclosing controller, so that the grid-connected switch controller controls the grid-connected switches to trip based on the control information after receiving the control information, and sends the off-grid message to the reclosing controller; a second control unit, used to control the outlet circuit breaker of the active distribution network to reclose through the reclosing controller after waiting for a second predetermined time after the reclosing controller receives the off-grid message; and a second ending unit, used to end the reclosing operation after determining that the outlet circuit breaker is reclosed.

[0025] Optionally, the reclosing device of the active distribution network also includes: a first acquisition unit, used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network after the reclosing controller does not receive the off-grid message; a first determination unit, used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; an operation unit, used to perform a reclosing operation on the active distribution network when the reclosing action duration arrives and it is detected that all the inverter-type distributed power sources have been off-grid.

[0026] Optionally, the first acquisition module includes: a second acquisition unit, configured to acquire the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network through a first formula, wherein the first formula is: t a Indicates the duration of the anti-islanding protection, U p.u. It represents the measured per unit value of the bus side voltage of the active power distribution network.

[0027] Optionally, the first acquisition module includes: a second determination unit, configured to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action through a second formula, wherein the second formula is: t rIndicates the duration of the reclosing action, t a represents the duration of the anti-islanding protection, Δt represents the fault arc extinction time of the active distribution network, t Ⅱ Indicates the action time of current II in stage protection, t Ⅲ It indicates the action time of current stage III in the stage protection. Stages I, II and III refer to the stage current protection configured for the distribution line outlet protection.

[0028] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, wherein the computer-readable storage medium includes a stored program, wherein the program executes any one of the above-mentioned methods for reclosing an active power distribution network.

[0029] According to another aspect of an embodiment of the present invention, a processor is further provided, wherein the processor is used to run a program, wherein the program executes any one of the above-mentioned active power distribution network reclosing methods when running.

[0030] According to another aspect of an embodiment of the present invention, a computer program product is provided, comprising computer instructions, wherein when the computer instructions are executed by a processor, any one of the above-mentioned methods for reclosing an active power distribution network is executed.

[0031] In an embodiment of the present invention, when it is determined that the active distribution network starts reclosing, the reclosing mode of the active distribution network is determined; when it is determined that the reclosing mode is a no-voltage detection mode, the reclosing controller of the active distribution network detects whether the active distribution network has a no-voltage detection condition to obtain a first detection result; when it is determined that the reclosing mode is a communication reclosing mode, the reclosing controller detects whether the active distribution network has a communication condition to obtain a second detection result; when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping, the active distribution network is controlled to perform a no-voltage detection reclosing operation; when the second detection result indicates that the active distribution network has a communication condition, when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid, the active distribution network is controlled to perform a communication reclosing operation through the reclosing controller. Through the technical scheme provided by the present invention, the timing coordination of the time-limit adaptive reclosing switch with the staged current protection and the anti-islanding protection of the distributed power supply is achieved, so that the active distribution network can quickly reclose in the scenario where the communication and no-voltage detection conditions are not available. At the same time, the time-limit adaptive reclosing switch is coordinated with the no-voltage detection and communication type reclosing switch, so as to achieve the purpose of quickly reclosing in the scenario where the no-voltage detection or communication conditions are available, thereby achieving the technical effect of being applicable to all active distribution line reclosing application scenarios through the coordination relationship between the time-limit adaptive reclosing switch, the no-voltage detection reclosing switch and the communication type reclosing switch, thereby improving the versatility and reliability of the reclosing switch, and further solving the technical problem in the related technology that the active distribution network has many limitations when performing reclosing, resulting in low power supply reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 It is a hardware structure block diagram of a mobile terminal of a reclosing method for an active power distribution network according to an embodiment of the present invention;

[0034] Figure 2 is a flow chart of a reclosing method for an active power distribution network according to an embodiment of the present invention;

[0035] Figure 3 is a flow chart of a general active distribution network reclosing implementation scheme according to an embodiment of the present invention;

[0036] Figure 4 is a schematic diagram of the coordination relationship between the communication type reclosing switch and the time limit adaptive reclosing switch according to an embodiment of the present invention;

[0037] Figure 5is a circuit diagram of an active distribution network according to a reclosing method of an active distribution network according to an embodiment of the present invention;

[0038] Figure 6 is a line side voltage variation curve diagram according to an embodiment of the present invention;

[0039] Figure 7 is a current waveform diagram of protection QF2 according to an embodiment of the present invention;

[0040] Figure 8 is a schematic diagram of a reclosing device for an active power distribution network according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] As introduced in the background technology, in the related art, active distribution networks have many limitations when performing reclosing, resulting in a technical problem of low power supply reliability. In view of the above defects, in the embodiments of the present invention, a reclosing method and device for an active distribution network, a computer-readable storage medium, a processor, and a computer program product are provided.

[0044] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0045] The method embodiments provided in the embodiments of the present invention can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking running on a mobile terminal as an example, Figure 1FIG. 1 is a hardware structure block diagram of a mobile terminal for a reclosing method of an active power distribution network according to an embodiment of the present invention. Figure 1 As shown, the mobile terminal may include one or more ( Figure 1 Only one is shown in the figure) a processor 102 (the processor 102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA) and a memory 104 for storing data, wherein the mobile terminal may also include a transmission device 106 and an input / output device 108 for communication functions. It can be understood by those skilled in the art that Figure 1 The structure shown is only for illustration and does not limit the structure of the mobile terminal. Figure 1 More or fewer components as shown, or with Figure 1 Different configurations are shown.

[0046] The memory 104 can be used to store computer programs, for example, software programs and modules of application software, such as the computer program corresponding to the reclosing method of the active power distribution network in the embodiment of the present invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, that is, the above method is implemented. The memory 104 may include a high-speed random access memory, and may also include a non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some examples, the memory 104 may further include a memory remotely arranged relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-mentioned network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific example of the above-mentioned network may include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, referred to as NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0047] According to an embodiment of the present invention, a method embodiment of a reclosing method for an active distribution network is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0048] Figure 2is a flow chart of a reclosing method for an active power distribution network according to an embodiment of the present invention, such as Figure 2 As shown, the method comprises the following steps:

[0049] Step S202, when it is determined that the active distribution network starts reclosing, determine the reclosing mode of the active distribution network.

[0050] Optionally, the above-mentioned reclosing modes may include: a no-pressure detection mode, a communication mode and a time limit adaptive mode.

[0051] Figure 3 is a flow chart of a general active distribution network reclosing implementation scheme according to an embodiment of the present invention, such as Figure 3 As shown, after the reclosing switch is started, the way to check the reclosing switch is to check whether it is put into operation by the no-pressure check method, the communication reclosing switch, or both the no-pressure check and the communication methods, and then perform the corresponding operations respectively.

[0052] In this embodiment, when it is determined that the active distribution network starts the reclosing switch, the reclosing switch implementation mode of the active distribution network can be checked to ensure that the reclosing switch can be normally put into operation when the active distribution network is started, and the reclosing switch can be quickly put into operation when necessary to isolate the fault area in time.

[0053] Step S204, when it is determined that the reclosing mode is the no-voltage detection mode, the reclosing controller of the active distribution network detects whether the active distribution network meets the no-voltage detection condition to obtain a first detection result.

[0054] It should be noted that the above-mentioned reclosing controller is a device used to control the operation of the reclosing switch, which can monitor parameters such as current and voltage. When a fault or overload occurs in the distribution system, it can automatically control the operation of the reclosing switch to isolate the fault or cut off the overload area.

[0055] In this embodiment, when it is determined that the reclosing mode is the no-voltage check mode, the reclosing controller of the active distribution network can detect whether the no-voltage check condition is met to obtain a first detection result, wherein the first detection result can be that the no-voltage check condition is met or not, thereby determining whether the reclosing operation can be performed, ensuring that no voltage exists during the reclosing process, and protecting the equipment from damage.

[0056] Step S206, when it is determined that the reclosing mode is the communication reclosing mode, the reclosing controller detects whether the active power distribution network has communication conditions to obtain a second detection result.

[0057] In this embodiment, when it is determined that the reclosing mode is the communication reclosing mode, the reclosing controller can detect whether the communication conditions are met to obtain a second detection result, wherein the first detection result can be that the communication conditions are met or not, which can help determine whether the active distribution network can communicate with the reclosing controller, thereby ensuring the normal operation of the reclosing.

[0058] Step S208, when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping, the active distribution network is controlled to perform a voltage-free reclosing operation.

[0059] In this embodiment, it can be ensured that when the active distribution network performs a protection trip, the voltage on the line side is not 0, so as to avoid safety risks caused by misoperation of the reclosing switch when the power grid is 0. By detecting that the line side voltage is not 0, it can be confirmed that the line is operating normally. At this time, it is safe and reliable to control the active distribution network to perform the no-voltage reclosing operation, which can effectively prevent accidents caused by misoperation.

[0060] Step S210, when the second detection result indicates that the active distribution network has communication conditions, when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid, the reclosing controller controls the active distribution network to perform a communication-type reclosing operation.

[0061] It should be noted that the above-mentioned inverter interfaced distributed energy resource (IIDER) is a distributed energy system that uses an inverter to convert direct current into alternating current. The low voltage ride-through requirements of the IIDER connected to the line have been configured in the reclosing controller.

[0062] In this embodiment, when the detection result of the reclosing controller indicates that the active distribution network has the communication conditions, when the reclosing controller receives an off-grid message that all inverter-type distributed power sources in the active distribution network have been disconnected from the grid, the reclosing controller can control the active distribution network to perform a communication-type reclosing operation, thereby being able to isolate the off-grid inverter-type distributed power sources in time, avoiding interference or damage to the system by the inverter-type distributed power sources, and improving the degree of automation of the system.

[0063] like Figure 3 As shown in the figure, the specific implementation steps are as follows: 1) When a fault occurs in the distribution line, the system side and each IIDER simultaneously inject current into the fault point. 2) The distribution line outlet protection detects a fault, the protection acts and trips, and the reclosing controller obtains the bus side voltage U before tripping l, extract protection action information. The IIDER connected to the distribution line performs low voltage ride-through according to the low voltage ride-through requirements. 3) The reclosing switch is started and the reclosing switch is checked for input mode. 4) The reclosing switch action time is set according to the specific conditions of the application scenario and the reclosing switch input mode to determine whether the reclosing switch controller detects whether the no-voltage detection condition is met; determine whether the reclosing switch controller detects whether the communication condition is met; when the reclosing switch controller detects that the no-voltage detection reclosing switch and the communication reclosing switch are not put into use, the time-limited adaptive reclosing switch is started.

[0064] As can be seen from the above, in an embodiment of the present invention, when it is determined that the active distribution network starts the reclosing, the reclosing mode of the active distribution network is determined; when it is determined that the reclosing mode is the no-voltage detection mode, the reclosing controller of the active distribution network detects whether the active distribution network has the no-voltage detection condition to obtain a first detection result; when it is determined that the reclosing mode is the communication reclosing mode, the reclosing controller detects whether the active distribution network has the communication condition to obtain a second detection result; when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping, the active distribution network is controlled to perform the no-voltage detection reclosing operation; when the second detection result indicates that the active distribution network has the communication condition, the reclosing controller receives the communication condition from all the active distribution network. When an off-grid message is received indicating that the inverter-type distributed power source has been disconnected from the grid, the active distribution network is controlled by the reclosing controller to perform a communication-type reclosing operation, thereby achieving the timing coordination of the time-limit adaptive reclosing with the staged current protection and the distributed power source anti-islanding protection, so that the active distribution network can quickly reclose in scenarios where there are no communication and no-voltage detection conditions. At the same time, the time-limit adaptive reclosing is coordinated with the no-voltage detection and the communication-type reclosing, so that the purpose of rapid reclosing can be achieved in scenarios where there are no-voltage detection or communication conditions, thereby achieving the technical effect of being applicable to all active distribution line reclosing application scenarios through the coordination relationship between the time-limit adaptive reclosing, the no-voltage detection reclosing and the communication-type reclosing, thereby improving the versatility and reliability of the reclosing.

[0065] The technical solution provided by the embodiment of the present invention solves the technical problem in the related art that the active distribution network has many limitations when performing reclosing, resulting in low power supply reliability.

[0066] According to the above embodiment of the present invention, the reclosing method of the active distribution network also includes: when the first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping, determining that the active distribution network does not have the no-voltage detection condition, and locking the no-voltage detection reclosing operation of the active distribution network; obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been disconnected from the grid, performing a reclosing operation on the active distribution network.

[0067] It should be noted that the above-mentioned first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping. It may be the zero voltage of the three-phase metallic fault or the line-side voltage transformer disconnection problem. The conditions for checking the no-pressure reclosing switch are not met, and the no-pressure reclosing switch needs to be locked.

[0068] It should be noted that the above-mentioned anti-islanding protection is to prevent the distributed power sources from forming isolated operation and causing safety hazards. By calculating the anti-islanding protection duration, it can be ensured that corresponding measures are taken in time after the distributed power sources are disconnected from the grid.

[0069] In this embodiment, the voltage-free reclosing operation can be performed when the line-side voltage is not 0 before the protection trips. On the contrary, the voltage-free reclosing operation is locked, and then the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network is obtained, and then the reclosing action duration is calculated according to the anti-islanding protection duration and the protection action information to determine the timing of the reclosing action to ensure that the reclosing operation is performed within an appropriate time. When the reclosing action time arrives, it is ensured that all IIDERs are disconnected from the grid to avoid the formation of islanding operation again after the reclosing, and the reclosing action is executed to control the circuit breaker to reclose, and restore the normal operation of the power system.

[0070] In addition, since this embodiment is a scenario with the conditions for voltage-free detection, in order to further improve reliability, the time-limit adaptive reclosing switch can be used as a backup for the voltage-free detection reclosing switch. Specifically, when a distribution network line fails, if the line-side voltage is 0 before the protection trips, it may be a zero-voltage problem caused by a three-phase metallic fault or a broken line in the line-side voltage transformer, which does not meet the conditions for voltage-free detection reclosing switch. At this time, the voltage-free detection reclosing switch should be locked, and the reclosing time should be adjusted according to the waiting time set by the time-limit adaptive reclosing switch, thereby improving the reliability of the reclosing switch.

[0071] According to the above embodiment of the present invention, the reclosing method of the active distribution network also includes: when the second detection result indicates that the active distribution network does not have communication conditions, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been disconnected from the grid, performing a reclosing operation on the active distribution network.

[0072] In this embodiment, when the detection result of the reclosing controller on the active distribution network indicates that the active distribution network does not have the communication condition, the anti-islanding protection duration is obtained, and the reclosing action duration is calculated according to the anti-islanding protection duration and the protection action information. When the reclosing action time is reached, it is ensured that all IIDERs are disconnected from the network, and the reclosing operation is performed on the active distribution network, which can ensure the safe operation of the active distribution network and access to the main power grid.

[0073] According to the above-mentioned embodiment of the present invention, the active distribution network is controlled to perform a voltage-free reclosing operation, including: when it is detected that the line side voltage of the active distribution network is 0, after waiting for a first predetermined period of time, controlling the outlet circuit breaker of the active distribution network to reclose through a reclosing controller; after determining that the outlet circuit breaker is reclosed, ending the voltage-free reclosing operation.

[0074] In this embodiment, when it is detected that the line-side voltage of the active power distribution network is 0, after waiting for 0.3s (ie, the first predetermined time period), the outlet circuit breaker is controlled to reclose, and the reclosing process ends.

[0075] According to the above embodiment of the present invention, when the second detection result indicates that the active distribution network has the communication conditions, when the reclosing controller receives the off-grid message that all the inverter-type distributed power sources in the active distribution network have been off-grid, the active distribution network is controlled by the reclosing controller to perform a reclosing operation, including: sending control information for disconnecting the grid-connected switches of the inverter-type distributed power sources to the grid-connected switch controllers of the grid-connected switches of all the inverter-type distributed power sources according to the pre-configured topology information through the reclosing controller, so that the grid-connected switch controller controls the grid-connected switch to trip based on the control information after receiving the control information, and sends the off-grid message to the reclosing controller; after the reclosing controller receives the off-grid message, after waiting for a second predetermined time, the outlet circuit breaker of the active distribution network is controlled to reclose through the reclosing controller; after determining that the outlet circuit breaker is reclosed, the reclosing operation is ended.

[0076] In this embodiment, the reclosing controller can send control information for disconnecting the IIDER grid-connected switch to the controllers of all IIDER grid-connected switches according to the configured topology information. When the grid-connected switch controller of the IIDER receives the control instruction, it controls the grid-connected switch of the IIDER to trip, and sends back the status confirmation information that the IIDER has been off-grid to the reclosing controller. After confirming that the reclosing controller has received the confirmation message that all grid-connected IIDERs have been off-grid, the reclosing controller waits for 0.3s (i.e., the second predetermined time length) and then controls the outlet circuit breaker to reclose, thereby ending the reclosing process.

[0077] In addition, since the embodiment is a scenario with communication conditions, the time-limit adaptive reclosing switch can be used as a backup for the communication reclosing switch to further improve reliability. Figure 4 Schematic diagram of the coordination relationship between the communication type reclosing switch and the time limit adaptive reclosing switch according to an embodiment of the present invention. Figure 4 As shown, when a distribution line fails and the system protection device trips, the reclosing controller will quickly send an operation instruction to disconnect the IIDER to all connected IIDER grid-connected switches through a message. After receiving the instruction, the controllers of these IIDER grid-connected switches control the IIDER grid-connected switches to disconnect after the IIDER low voltage ride-through ends, so as to realize the IIDER off-grid. After ensuring that the IIDER grid-connected switch is in the disconnected state, a message is sent to the reclosing controller to confirm that the IIDER it monitors has been off-grid. If the reclosing controller does not receive the off-grid confirmation signal from the IIDER parallel switch controller due to communication link failure or other reasons, the logic calculation of the reclosing will be performed according to the action time of the time-limit adaptive reclosing configuration.

[0078] According to the above embodiment of the present invention, the reclosing method of the active distribution network also includes: after the reclosing controller does not receive the off-grid message, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been off-grid, performing a reclosing operation on the active distribution network.

[0079] In this embodiment, when the reclosing controller does not receive the off-grid message, the anti-islanding protection duration can be obtained, and the reclosing action duration can be determined according to the anti-islanding protection duration and the protection action information. When the reclosing action time arrives, it is ensured that all IIDERs are off-grid, the reclosing is actuated, and the circuit breaker is controlled to reclose.

[0080] According to the above embodiment of the present invention, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network includes: obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network through a first formula, wherein the first formula is: t a Indicates the duration of anti-islanding protection, U p.u. It represents the measured per unit value of bus voltage of active distribution network.

[0081] In this embodiment, the time required for the connected IIDER anti-islanding protection action can be calculated according to the first formula.

[0082] It should be noted that if there are multiple distributed power sources connected to the line, then t a Taking the maximum value of all IIDER anti-islanding protection action times, according to the first formula, the anti-islanding protection action time range is [0.625s, 2s], where t a is the estimated IIDER low voltage ride-through time, in seconds.

[0083] According to the above embodiment of the present invention, the reclosing action duration required for the active distribution network to perform reclosing is determined according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action, including: determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action by a second formula, wherein the second formula is: t r Indicates the duration of reclosing action, t a represents the duration of anti-islanding protection, Δt represents the arc extinction time of the active distribution network, t Ⅱ Indicates the action time of current II in stage protection, t Ⅲ It indicates the action time of current stage III in the stage protection. Stages I, II and III refer to the stage current protection configured for the distribution line outlet protection.

[0084] It should be noted that the above Δt is the fault arc extinction time, which can be 0.3s.

[0085] In this embodiment, the reclosing controller can obtain t according to the first formula a and protection action information, calculate the reclosing action time t according to the second formula r .

[0086] In addition, it should be noted that the protection action information here refers to the action information of the outlet protection, which selects the corresponding calculation expression according to whether it is the current stage I, II or III protection action in the outlet stage current protection.

[0087] The above-mentioned Section I, Section II and Section III refer to the staged current protection configured at the outlet of the distribution line, including the quick-break protection that reacts instantaneously to the increase in the short-circuit current amplitude, the time-limited current quick-break protection coordinated with the quick-break of the lower-level line, and the time-limited overcurrent protection that avoids the maximum load current setting, which are respectively called current Section I, Section II and Section III protection.

[0088] Taking the scenario where the active distribution network has the condition of no-voltage detection as an example, the coordination relationship between the no-voltage detection and the time-limit adaptive reclosing in this embodiment is explained. Figure 5 is a circuit diagram of an active distribution network according to a reclosing method of an active distribution network according to an embodiment of the present invention, such as Figure 5 As shown, the specific steps are as follows: 1) When a fault occurs at point F1, the current flowing through the line outlet protection QF2 increases, the bus A voltage decreases, and the IIDER enters the low voltage ride-through state. 2) After the protection QF2 detects the fault current, it trips the circuit breaker, the reclosing starts, and the reclosing controller obtains the bus side voltage U1 and the line side voltage U2 before tripping. The low voltage ride-through requirements of the IIDER connected to the line have been configured in the reclosing controller. 3) Because IIDER1 and IIDER2 are still in the grid-connected state and continue to provide fault current to the fault point, the fault point does not extinguish the arc. When the low voltage ride-through of IIDER1 and IIDER2 ends, the anti-islanding protection QF3 acts to cut off IIDER1, and the anti-islanding protection QF5 acts to cut off IIDER2. At this time, there is no fault current flowing through the fault point, the arc is quickly extinguished, and the instantaneous fault disappears. 4) If the line voltage is 0 before the protection trips, the reclosing controller determines the reclosing waiting time according to the time-limited adaptive reclosing action logic: the reclosing waiting time is set according to the bus voltage and the low voltage crossing requirements of IIDER1 and IIDER2. When the reclosing waiting time is up, ensure that both IIDER1 and IIDER2 are disconnected from the grid; otherwise, if the line voltage is not 0 before the protection trips, a voltage-free reclosing check can be performed. 5) The circuit breaker QF2 is extended by 0.3s on the basis of the reclosing waiting time (considering the time taken for the circuit breaker to reset and the arc extinguishing and de-ionizing time). When the preset delay time is up, the reclosing action is performed to control the circuit breaker QF2 to reclose, and the line is restored to power supply. If it is a transient fault, the reclosing is successful and the power supply of this line is restored; if it is a permanent fault, QF2 accelerates and trips again.

[0089] Table 1 is a table of setting values ​​of protection switches. As shown in Table 1, the phase-to-phase short-circuit fault points are set at points F1 and F2 in the figure. Fault point F1 is set at 0.2 km from bus A on this line, and fault point F2 is set at 2 km from bus A.

[0090] Table 1

[0091]

[0092]

[0093] Figure 6 is a line side voltage variation curve diagram according to an embodiment of the present invention, Figure 7 is a current waveform diagram of protection QF2 according to an embodiment of the present invention. When a three-phase short circuit fault occurs at point F2 at 0.2s, the line side voltage and the fault current at protection QF2 are respectively as follows: Figure 6 , 7 As shown in the figure, when a three-phase short circuit fault occurs at point F2, 0.3s after the fault occurs, the current protection stage II of QF2 trips. About 0.625s after the fault occurs, the anti-islanding protection of IIDER1 and IIDER2 is activated, and both IIDER1 and IIDER2 are disconnected from the grid and exit operation. The line-side voltage transformer detects the no-pressure reclosing switch. After waiting for 0.3s, the reclosing device is activated to control the circuit breaker QF2 to reclose, and the distribution line resumes power supply. If the fault is a permanent fault, the line protection QF2 will trip again to remove the fault.

[0094] In addition, if the voltage transformer on the line side is disconnected and other problems occur, causing the voltage-free reclosing to fail, the backup time-limited adaptive reclosing method is activated and set according to the bus voltage. The anti-islanding protection action time is 1.42s, and Δt is taken as 0.3s. Since the current protection stage II action time is 0.3s, the actual reclosing waiting time is 1.42s. After waiting for 1.42s, the reclosing device is activated, controlling the circuit breaker QF2 to reclose, and the distribution line resumes power supply.

[0095] Through the technical solution provided by the above-mentioned embodiments of the present invention, for scenarios where there are no voltage detection and communication conditions, the coordination relationship between the time-limit adaptive reclosing method and the three-stage current protection and anti-islanding protection of the distribution network is comprehensively considered, and the reclosing waiting time can be further reduced. In this scenario, according to the different protection action times, the reclosing action time can be shortened by up to 2s compared with the traditional reclosing scheme through delay coordination; for scenarios where the voltage detection fails, the coordination method of the voltage detection and the time-limit adaptive reclosing proposed in the present invention can improve the reliability of the reclosing; for scenarios with communication conditions, considering the problem that the reclosing cannot operate correctly due to reasons such as communication, the time-limit adaptive reclosing is coordinated with the communication-type reclosing to improve the reliability of the reclosing.

[0096] That is, the above technical solution provided by the embodiment of the present invention comprehensively considers factors such as versatility and reliability, and can be applied to active distribution networks in various scenarios. In scenarios where there are no communication and no-voltage detection conditions, the time-limit adaptive reclosing method can be used to achieve rapid reclosing of the active distribution network. The time-limit adaptive reclosing refers to the use of the bus side voltage measured before the export circuit breaker protection trips and the IIDER off-grid time pre-set according to the regulations to automatically adjust the action time of the reclosing. It does not require a line-side voltage transformer, is not dependent on communication conditions, and has good economy. Compared with the traditional reclosing scheme that achieves coordination through delay, it can shorten the power outage time and improve the reliability of power supply. In scenarios with no-voltage detection or communication conditions, rapid reclosing can be achieved. If a communication failure or a voltage transformer disconnection is detected, the time-limit adaptive reclosing scheme is used as a backup to improve the reliability of power supply.

[0097] It should be noted that, for the aforementioned method embodiments, for the sake of simplicity, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the present application is not limited by the described order of actions, because according to the present application, certain steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present application.

[0098] Through the description of the above implementation methods, those skilled in the art can clearly understand that the method according to the above embodiment can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for a terminal device (which can be a mobile phone, computer, server, or network device, etc.) to execute the methods of each embodiment of the present application.

[0099] According to an embodiment of the present invention, there is also provided a reclosing device for an active distribution network for implementing the above-mentioned reclosing method for an active distribution network. Figure 8 Schematic diagram of a reclosing device for an active power distribution network according to an embodiment of the present invention, Figure 8 As shown, the device includes: a first determination module 801, a first detection module 803, a second detection module 805, a first operation module 807 and a second operation module 809. The risk analysis device in the operation process of the power grid is described below.

[0100] The first determining module 801 is used to determine the reclosing mode of the active distribution network when it is determined that the active distribution network starts the reclosing.

[0101] The first detection module 803 is used to detect whether the active distribution network has the no-voltage detection condition through the reclosing controller of the active distribution network when it is determined that the reclosing mode is the no-voltage detection mode, and obtain a first detection result.

[0102] The second detection module 805 is used to detect whether the active power distribution network has communication conditions through the reclosing controller when it is determined that the reclosing mode is the communication reclosing mode, so as to obtain a second detection result.

[0103] The first operating module 807 is used to control the active distribution network to perform a voltage-free reclosing operation when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping.

[0104] The second operation module 809 is used to control the active distribution network to perform a communication reclosing operation through the reclosing controller when the second detection result indicates that the active distribution network has communication conditions and when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid.

[0105] It should be noted here that the above-mentioned first determination module 801, first detection module 803, second detection module 805, first operation module 807 and second operation module 809 correspond to steps S202 to S210 in the above-mentioned embodiments, and the five modules are the same as the instances and application scenarios implemented by the corresponding steps, but are not limited to the contents disclosed in the above-mentioned embodiments.

[0106] As can be seen from the above, in the scheme recorded in the above-mentioned embodiment of the present invention, first, the first determination module can be used to determine the reclosing mode of the active distribution network when it is determined that the active distribution network starts the reclosing; then, the first detection module can be used to detect whether the active distribution network has the no-voltage detection condition through the reclosing controller of the active distribution network when it is determined that the reclosing mode is the no-voltage detection mode, and obtain a first detection result; then, the second detection module can be used to detect whether the active distribution network has the communication condition through the reclosing controller when it is determined that the reclosing mode is the communication reclosing mode, and obtain a second detection result; secondly, the first operation module can be used to control the active distribution network to perform the no-voltage detection reclosing operation when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping; finally, the second operation module can be used to detect whether the active distribution network has the communication condition when the second detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping; When the active distribution network has the conditions for communication, when the reclosing controller receives the off-grid message that all inverter-type distributed power sources in the active distribution network have been off-grid, the reclosing controller controls the active distribution network to perform the communication reclosing operation, thereby achieving the timing coordination of the time-limit adaptive reclosing with the staged current protection and the distributed power source anti-islanding protection, so that the active distribution network can quickly reclose in the scenario where there are no communication and no-voltage detection conditions. At the same time, the time-limit adaptive reclosing is coordinated with the no-voltage detection and the communication reclosing, so as to achieve the purpose of quickly reclosing in the scenario where there are no-voltage detection or communication conditions, thereby achieving the technical effect of being applicable to all active distribution line reclosing application scenarios through the coordination relationship between the time-limit adaptive reclosing, the no-voltage detection reclosing and the communication reclosing, thereby improving the versatility and reliability of the reclosing.

[0107] The technical solution provided by the embodiment of the present invention solves the technical problem in the related art that the active distribution network has many limitations when performing reclosing, resulting in low power supply reliability.

[0108] In an optional embodiment, the reclosing device of the active distribution network also includes: a first processing module, which is used to determine that the active distribution network does not have the no-voltage detection condition when the first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping, and lock the no-voltage detection reclosing operation of the active distribution network; a first acquisition module, which is used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; a second determination module, which is used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; a third operation module, which is used to perform a reclosing operation on the active distribution network when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been disconnected from the grid.

[0109] In an optional embodiment, the reclosing device of the active distribution network further includes: a second acquisition module, which is used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network when the second detection result indicates that the active distribution network does not have communication conditions; a third determination module, which is used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; and a fourth operation module, which is used to perform a reclosing operation on the active distribution network when the reclosing action duration arrives and it is detected that all inverter-type distributed power sources have been disconnected from the grid.

[0110] In an optional embodiment, the first operating module includes: a first control unit, which is used to control the reclosing of the outlet circuit breaker of the active distribution network through a reclosing controller after waiting for a first predetermined period of time when it is detected that the line side voltage of the active distribution network is 0; and a first ending unit, which is used to end the no-voltage reclosing operation after determining that the outlet circuit breaker is reclosed.

[0111] In an optional embodiment, the second operation module includes: a sending unit, which is used to send control information for disconnecting the grid-connected switches of the inverter-type distributed power sources to the grid-connected switch controllers of the grid-connected switches of all inverter-type distributed power sources through the reclosing controller according to pre-configured topology information, so that the grid-connected switch controller controls the grid-connected switch to trip based on the control information after receiving the control information, and sends a grid-off message to the reclosing controller; a second control unit, which is used to control the outlet circuit breaker of the active distribution network to reclose through the reclosing controller after waiting for a second predetermined time after the reclosing controller receives the grid-off message; and a second ending unit, which is used to end the reclosing operation after determining that the outlet circuit breaker is reclosed.

[0112] In an optional embodiment, the reclosing device of the active distribution network further includes: a first acquisition unit, used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network after the reclosing controller does not receive the off-grid message; a first determination unit, used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; an operation unit, used to perform a reclosing operation on the active distribution network when the reclosing action duration arrives and it is detected that all inverter-type distributed power sources have been off-grid.

[0113] In an optional embodiment, the first acquisition module includes: a second acquisition unit, which is used to obtain the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network through a first formula, wherein the first formula is: t a Indicates the duration of anti-islanding protection, Up.u. It represents the measured per unit value of bus voltage of active distribution network.

[0114] In an optional embodiment, the first acquisition module includes: a second determination unit, which is used to determine the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action through a second formula, wherein the second formula is: t r Indicates the duration of reclosing action, t a represents the duration of anti-islanding protection, Δt represents the arc extinction time of the active distribution network, t Ⅱ Indicates the action time of current II in stage protection, t Ⅲ It indicates the action time of current stage III in the stage protection. Stages I, II and III refer to the stage current protection configured for the distribution line outlet protection.

[0115] According to another aspect of an embodiment of the present invention, a processor is further provided, and the processor is used to run a program, wherein when the program is run, any one of the above-mentioned active power distribution network reclosing methods is executed.

[0116] According to another aspect of an embodiment of the present invention, there is further provided a computer program product, comprising computer instructions, wherein when the computer instructions are executed by a processor, any one of the above-mentioned methods for reclosing an active power distribution network is executed.

[0117] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium comprising a stored program, wherein the program executes any one of the above-mentioned methods for reclosing an active power distribution network.

[0118] Optionally, in this embodiment, the computer-readable storage medium may be located in any one of the computer terminals in a computer terminal group in a computer network, or in any one of the communication devices in a communication device group.

[0119] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: when it is determined that the active distribution network starts reclosing, the reclosing mode of the active distribution network is determined; when it is determined that the reclosing mode is a no-voltage detection mode, the reclosing controller of the active distribution network detects whether the active distribution network has a no-voltage detection condition to obtain a first detection result; when it is determined that the reclosing mode is a communication reclosing mode, the reclosing controller detects whether the active distribution network has a communication condition to obtain a second detection result; when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping, the active distribution network is controlled to perform a no-voltage detection reclosing operation; when the second detection result indicates that the active distribution network has a communication condition, when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been disconnected from the grid, the active distribution network is controlled to perform a communication reclosing operation through the reclosing controller.

[0120] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: when the first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping, determining that the active distribution network does not have the condition for voltage detection, and locking the voltage detection reclosing operation of the active distribution network; obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been disconnected from the grid, performing a reclosing operation on the active distribution network.

[0121] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: when the second detection result indicates that the active distribution network does not have communication conditions, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been disconnected from the grid, performing a reclosing operation on the active distribution network.

[0122] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: when it is detected that the line side voltage of the active distribution network is 0, after waiting for a first predetermined period of time, controlling the outlet circuit breaker of the active distribution network to reclose through a reclosing controller; after determining that the outlet circuit breaker is reclosed, ending the no-voltage reclosing operation.

[0123] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: sending control information for disconnecting the grid-connected switches of all inverter-type distributed power sources to the grid-connected switch controllers of the grid-connected switches of all inverter-type distributed power sources according to pre-configured topology information through the reclosing controller, so that the grid-connected switch controller controls the grid-connected switch to trip based on the control information after receiving the control information, and sends an off-grid message to the reclosing controller; after the reclosing controller receives the off-grid message, after waiting for a second predetermined time period, the reclosing controller controls the outlet circuit breaker of the active distribution network to reclose; after determining that the outlet circuit breaker is reclosed, the reclosing operation is terminated.

[0124] Optionally, in this embodiment, the computer-readable storage medium is configured to store program codes for executing the following steps: after the reclosing controller does not receive the off-grid message, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; when the reclosing action duration arrives, if it is detected that all inverter-type distributed power sources have been off-grid, performing a reclosing operation on the active distribution network.

[0125] Optionally, in this embodiment, the computer-readable storage medium is configured to store a program code for executing the following steps: obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network by a first formula, wherein the first formula is: t a Indicates the duration of anti-islanding protection, U p.u. It represents the measured per unit value of bus voltage of active distribution network.

[0126] Optionally, in this embodiment, the computer-readable storage medium is configured to store a program code for executing the following steps: determining the reclosing action duration required when the active distribution network performs reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action by a second formula, wherein the second formula is: t r Indicates the duration of reclosing action, t a represents the duration of anti-islanding protection, Δt represents the arc extinction time of the active distribution network, t Ⅱ Indicates the action time of current II in stage protection, t Ⅲ It indicates the action time of current stage III in the stage protection. Stages I, II and III refer to the stage current protection configured for the distribution line outlet protection.

[0127] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0128] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0129] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0130] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0131] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0132] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0133] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A reclosing method for an active distribution network, characterized in that: include: When it is determined that the active distribution network starts reclosing, determining the reclosing mode of the active distribution network; When it is determined that the reclosing mode is a no-voltage detection mode, detecting whether the active distribution network meets the no-voltage detection condition by means of a reclosing controller of the active distribution network, and obtaining a first detection result; When it is determined that the reclosing mode is a communication reclosing mode, detecting whether the active power distribution network has a communication condition by the reclosing controller to obtain a second detection result; When the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping, the active distribution network is controlled to perform a voltage-free reclosing operation; When the second detection result indicates that the active distribution network has the communication conditions, when the reclosing controller receives an off-grid message indicating that all inverter-type distributed power sources in the active distribution network have been off-grid, the reclosing controller controls the active distribution network to perform a communication-type reclosing operation.

2. The reclosing method for active power distribution network according to claim 1, characterized in that: Also includes: When the first detection result indicates that the voltage on the line side of the active distribution network is 0 before the protection tripping, determining that the active distribution network does not meet the no-voltage detection condition, and locking the no-voltage detection reclosing operation of the active distribution network; Obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; Determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; When the reclosing action duration arrives, if it is detected that all the inverter-type distributed power sources have been disconnected from the grid, a reclosing operation is performed on the active power distribution network.

3. The reclosing method for active power distribution network according to claim 1, characterized in that: Also includes: When the second detection result indicates that the active distribution network does not have a communication condition, obtaining an anti-islanding protection duration required for an anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network; Determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; When the reclosing action duration arrives, if it is detected that all the inverter-type distributed power sources have been disconnected from the grid, a reclosing operation is performed on the active power distribution network.

4. The reclosing method for an active power distribution network according to claim 1, characterized in that: Controlling the active power distribution network to perform a voltage-free reclosing operation, including: When it is detected that the line side voltage of the active power distribution network is 0, after waiting for a first predetermined time, controlling the outlet circuit breaker of the active power distribution network to reclose through the reclosing controller; After determining that the outlet circuit breaker is reclosed, the voltage-free reclosing operation is terminated.

5. The reclosing method for active power distribution network according to claim 1, characterized in that: When the second detection result indicates that the active distribution network has the communication condition, when the reclosing controller receives the off-grid message that all the inverter-type distributed power sources in the active distribution network have been off-grid, the active distribution network is controlled by the reclosing controller to perform a reclosing operation, including: Sending control information for disconnecting the grid-connected switch of the inverter-type distributed power source to the grid-connected switch controllers of the grid-connected switches of all the inverter-type distributed power sources according to the pre-configured topology information by the reclosing controller, so that the grid-connected switch controller controls the grid-connected switch to trip based on the control information after receiving the control information, and sends the off-grid message to the reclosing controller; After the reclosing controller receives the off-grid message, it waits for a second predetermined time and then controls the outlet circuit breaker of the active power distribution network to reclose through the reclosing controller; After determining that the outlet circuit breaker is reclosed, the reclosing operation is ended.

6. The reclosing method for active power distribution network according to claim 5, characterized in that: Also includes: After the reclosing controller fails to receive the off-grid message, obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active power distribution network; Determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action; When the reclosing action duration arrives, if it is detected that all the inverter-type distributed power sources have been disconnected from the grid, a reclosing operation is performed on the active power distribution network.

7. The reclosing method for an active power distribution network according to any one of claims 2, 3 and 6, characterized in that: Obtaining the anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network, including: The anti-islanding protection duration required for the anti-islanding protection action of the inverter-type distributed power source connected to the active distribution network is obtained by a first formula, wherein the first formula is: t a Indicates the duration of the anti-islanding protection, U p.u. It represents the measured per unit value of the bus side voltage of the active power distribution network.

8. The reclosing method for an active power distribution network according to any one of claims 2, 3 and 6, characterized in that: Determining the reclosing action duration required for the active distribution network to perform reclosing according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action, including: The reclosing action duration required for the active distribution network to perform reclosing is determined by a second formula according to the anti-islanding protection duration and the protection action information corresponding to the distribution line outlet protection action, wherein the second formula is: t r Indicates the duration of the reclosing action, t a represents the duration of the anti-islanding protection, Δt represents the fault arc extinction time of the active distribution network, t Ⅱ Indicates the action time of current II in stage protection, t Ⅲ It indicates the action time of current stage III in the stage protection. Stages I, II and III refer to the stage current protection configured for the distribution line outlet protection.

9. A reclosing method and device for an active power distribution network, characterized in that: include: A first determination module is used to determine the reclosing mode of the active distribution network when it is determined that the active distribution network starts the reclosing; A first detection module is used to detect whether the active distribution network has a no-voltage detection condition through the reclosing controller of the active distribution network when it is determined that the reclosing mode is a no-voltage detection mode, so as to obtain a first detection result; A second detection module is used to detect whether the active power distribution network has communication conditions through the reclosing controller when it is determined that the reclosing mode is a communication reclosing mode, so as to obtain a second detection result; A first operating module, configured to control the active distribution network to perform a voltage-free reclosing operation when the first detection result indicates that the voltage on the line side of the active distribution network is not 0 before the protection tripping; The second operating module is used to control the active distribution network to perform a communication reclosing operation through the reclosing controller when the second detection result indicates that the active distribution network has communication conditions and when the reclosing controller receives an off-grid message that all inverter-type distributed power sources in the active distribution network have been off-grid.

10. A computer program product comprising computer instructions, characterized in that: When the computer instructions are executed by the processor, the reclosing method for the active power distribution network as claimed in any one of claims 1 to 8 is performed.

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